电子设计竞赛直流稳定电源设计报告.doc

直流稳定电源（A题）设计报告 摘 要: 本设计采用单片机AT89C52作为系统的控制核心,制作了一个可稳定输出电流或电压的直流稳定电源。设计可分为七个模块：电源模块、稳压源模块、稳流源模块、DC-DC变换器模块、键盘模块、显示模块和系统控制模块。稳压电源采用串联反馈式稳压电路，主要由三端式集成稳压器LM317和运算放大器LM324构成。稳压电源和负载构成恒流源，并通过程序控制稳压源与稳流源电路之间的转换。DC-DC变换器采用双管自激谐振式振荡电路，稳压电源输出的小电压经DC-DC变换器输出较大的直流电压。本设计可实现电压预置，数码显示输出电压和电流，输出可步进（加、减）调节，恒压和恒流电路切换等功能。此外，A/D可将数据反馈一次对误差进行校正，稳压电路具有过热和过流保护功能，当电路出现故障时可自动恢复。 关键字：键盘控制，单片机，稳压源，稳流源，DC-DC变换器 A Constant Direct Current Electrical Source Abstract: A DC source, which uses a micro-control unit (MCU) AT89C52 as its kernel unit, is designed for supplying constant voltage or constant current. The system is consist of a center control unit, a power supply, a constant voltage source, a constant current source, a keyboard input unit, a digital display unit, and a DC-DC unit. A constant voltage unit is composed of feedback constant voltage circuit in series by integrated chip LM317 and a integrated operator LM324.A constant current source is implemented by a constant voltage source and a sampling resistor, and the output of current or voltage is chosen by a relevant program. The DC-DC converter is realized by a double-tube self-excitation oscillating circuit. The output can be predefined by MCU keyboard, changed in step and displayed in digital by LED. Moreover, it can be protected from damage of over-heat and over-burden, and can be resumed automatically from ill-work. Key words：keyboard controlmicro chip controller, constant voltage source, constant current source, DC－DC converter 目 录 引言-------------------------------------------------------------- 3 1． 系统设计----------------------------------------------------3 1.1 设计任务及要求---------------------------------------------3 1.2 总体设计方案-----------------------------------------------4 1.2.1 设计思路----------------------------------------------4 1.2.2 方案论证与比较----------------------------------------4 1.2.3 系统组成----------------------------------------------8 2.设计实现--------------------------------------------9 2.1 单元电路设计------------------------